Current disc drives store information on rotating discs that are typically either optical or magnetic. Magnetic discs are coated with a magnetizable medium on which data is recorded. The recorded information is arranged typically on concentric tracks around the axis of rotation of the discs. One or more transducers, commonly referred to as “heads”, are movably positioned over the disc surfaces to read and write data from and to the rotating discs. The heads are mounted on an actuator that positions the heads over and moves them from one track to another on the disc. The sheer volume of magnetic disc drive production is increasing every year. In addition, the data density on each of the disc surfaces is being increased every year that require drive designs to be easily manufacturable. The size, or “form factor”, of each generation of disc drives is continually getting smaller. The smallest drive currently in the market is a one-inch drive, which is in the form factor of a CF card (Compact Flash, type II). The type II CF form factor requires an overall thickness of no more than 5.5 mm. However, there is a continuing need to reduce the size of the drive even smaller without sacrificing capacity and performance.
An exploded view of the primary components of a base plate and printed circuit board assembly 100 for a conventional one-inch disc drive is shown in FIG. 1. A cross sectional view of the assembly 100 is shown in FIG. 2. The assembly 100 includes a base plate 102 to which various components of the disc drive will be subsequently mounted. Fastened to the bottom of the base plate 102 is a printed circuit board assembly 104. Finally, fastened to the bottom of the printed circuit board (PCB) assembly 104 is a printed circuit board (PCB) shield 106. These three components, the base plate 102, the PCB assembly 104, and the PCB shield 106, are mechanically assembled together in a conventional manner as is shown in the cross sectional view of FIG. 2. Here it can be seen that the PCB assembly 104 is spaced from both the PCB shield 106 and the base plate 102 by gaps 108 and 110. The drive motor coils 114 are installed in the base plate 102 before the PCB assembly 104 is installed on the base plate 102, thus requiring a drive motor connector having pins 116 to be present to contact with pads on the PCB assembly 104 when the PCB assembly 104 is joined with the base plate 102. This current base plate 102, at its thinnest, is about 0.5 mm thick. Reducing this thickness further leads to very severe structural instabilities.
One current challenge is to design a disc drive in a CF type I size. Such a drive has an overall thickness requirement of only 3.3 mm. There are no disc drives available that have a 3.3 mm thickness. A drive having a design thickness of only 3.3 mm has a number of problems. The base plate upon which the actuator and disc spin motor both are mounted becomes so thin as to be unacceptably structurally weakened. Thus a new concept of a base plate is needed that is both thin enough and strong enough to adequately support the moving components within the disc drive yet and, at the same time, permit a maximum thickness of the drive to be limited to 3.3 mm total form factor. The present invention provides a solution to this and other problems, and offers other advantages over the prior art.